Chocking device for vehicle lifts



Nov. 9, 1937. y J.M. cuNNx-:EN I 250%3-76 r f CHOCKING DEVICE FORVEHICLE -LIFTS v `Filed Aug. 23, A19321 2 sheets-sheet 2 ATTORNEYPatented Nov. 9, 1937 UNITED STATES PATENT oFFicE CHCCKIN G DEVICE FonVEHICLE mrs James M. Cunneen,' Jersey City, N. J., assignor to TheLubrication Corporation, a corporation of Delaware Application August23,

8 Claims.

This invention relates to improvements in motor vehicle -lifts of theso-called roll-on or drive-on type and more particularly to automaticchocking means for restraining a motor chock automatically assumes aposition so obstructing one of the wheels of the vehicle that thevehicle is restrained from rolling oi the track. Among the various formsof automatic chocking means that have so far been proposed, a lcommonform utilizes the ramps or aprons that are ordinarily disposed at theends of the runways or tracks to operate the chocks in such a manner asto cause the chocks torise and fall with respect to the iloor of thetracks or runways as the tracks are elevated and lowered'respectively.'In such type of chock mechanism, the pivoted ramp or apron is connectedwith the chock through a linkage so that the dropping of the `ramp underthe influence of gravity as the lift rises, causes the chock to riseinto chock- 30 ing position. As the lift is lowered the ramp engages`the ground and, through the linkage,v

pulls the chock downK out of chocking position. Some chocks are operatedby counterweights other than the ramps but are otherwise similar inconstruction and operation.

There is a disadvantage in such types of automatic chock. Since themechanism arranged to move the chock out of chocking position ispractically positive in its operation, serious damage to the linkagebetween the ramp and the chocks or to the chocks or ramps, etc., may.occur, if, as the ramps engage with the ground when the track islowered, the chocks are held against movement because of engagement ofthe vehicle Wheels therewith.

An object, therefore, of my present invention is to provide an improvedautomatic chock for v motor vehicle lifts wherein the chocking membersare elevated by automatic means through positive linkage as the track iselevated and lwh'ereinlost motion is provided between the chock membersvand their operating means, effective only during the lowering of thetrack, thereby to eliminate abusivestrain upon the operating elementsolf .5 the chocking means and/or upon other parts.

Another object is to provide an automatic chocking means wherein thechock members when in their elevated positions, are locked.

- against movement until the track is lowered to a position near thelower limit of its travel,

Chicago, lll.,

1934, serial No. 741,040 (c1. 254-89) A further object is to provide, inan automatic .chocking means an arrangement whereby the chock membersand operating means therefor may be wholly independent of the motorvehicle ramps at the adjacent end of the track.

Other objects, the advantages and uses of the invention, will, orshould, become apparent after reading the following description andclaims and after consideration of the drawings, forming a part of thisspecification, wherein:

Fig. l is a side elevation' of a motor vehicle lift incorporating myimproved automatic vehicleY chock;

Fig. 2 is a top plan View of the chock mechanism illustrated in Fig. A1;

Fig. 3 is a sectional view along the line llI--m of Fig. 2;

Fig. 4 is a sectional view'along the line lTV-EV of Fig. 2; i

Fig. 5 is a sectional view along the line V-V of Fig.' 2, and

Fig. 6 is a. fragmentary View of another form of the chock releasemechanism illustrated in Fig. 5.

I have selected for illustration herein a motor vehicle lift comprising,a plunger 2 mounted for reciprocation upon a vertical axis' andcarrying, at its'upper end, a horizontal vehicle supporting track 3. Thetrack may be raised and lowered by hydraulic operation of the plunger 2,by means not shown. If desired one end of the lift may be permanentlyclosed through the medium of cross rods 4 at adjacent ends of theparallel runways thus to preclude the displacement of the vehicle vfromthat end of the lift. The opposite end of the lift may have each trackprovided with a ramp 5, pivotally mounted on a hinge pin 6 that' maypass through eyes 1 formed at the end of the track.

Each' of the chocking means, there being one for each runway includes achock plate 8 pivotally mounted at 9 upon the hinge pin E and adaptednormally to lie in a plane common toV the track runwayrwithin a cut-awayportion l0' be arranged to lie at along its surface where it' will oiferno obstruction. 'Ihe -mechanism for elevating the chock 8 and foi'locking the member in this position when the track is elevated may besupported upon a steel' angle Il ilxed to the under surface'of the trackrunway.- 'I'he angle Il, aside from serving as a. support for theoperating mechanism, aords reinforcement forthe recessed or cut-awayportion of the runway. This mechanism may comprise a lever I2 pivotallymounted at I 3 upon lugs Il secured to the angle II, and provided at itsupper end with a grooved roller I5. The opposite or rearward end of thelever I2 may be formed, as shown at ISA, for receiving one end of acompression spring I 6 thereupon, the opposite end of the spring beinglocated within a circular boss I1 on the underside of the track runway.'I'he force of the spring I6 tends normally to maintain the lever I2 inthe position shown at Fig. 3, which position Vis maintained at all timeswhen the track is elevated and a shoe I8, provided at the rearward endof the lever I2, is free of the ground or other supporting surface 22upon which the motor vehicle lift is mounted.

A metal plate I 9 iixed to the underside of the chock plate 8, as by thewelding of integral lugs 2l thereof to the underside of the chock plate,provides a means for rolling but otherwise free engagement between thechock plate and the lever I2, through the reception of the lower andinclined edge 2| of the plate I9 within the groove of the roller I5.I'his arrangement causes the chock plate 8 to swing upwardly upon itspivotal support 6 when the lever I2 is moved to the position of Fig. 3by force of the spring I6. The operation of the chocking means takesplace whenever the lift is elevated suillciently to permit the shoe I8upon the lower end of the lever I2 to become disengaged from the groundor supporting surface 22. When the lift is lowered, the lever I2 iscaused to assume the dotted line position shown in Fig. 3 against theforce of the spring Ii because of engagement of the shoe I8 with thesurface 22. However, it does not necessarily follow that the chock plate8 will assume the position shown in Fig. 2 at this time for, if theplate is restrained against falling as by engagement of the tire of thevehicle therewith, it may be held temporarily in its elevated positionuntil the vehicle is rolled suiilciently to disengage the tire from thechock or out of the path of movement of the chock whereupon the chockmay fall of its own weight to its inoperative position. 'I'hroughout theraising and lowering of the track the-ramp 5 is free to swing upon itspivotal support 6, thus to provide a convenient approach for the vehicleto and from the track when the track is lowered, but the chockmechanisrn is unaiected thereby.

In Figs. 4 and 5, I have illustrated automatic means for locking thechock plate 8 in its elevated position at all times when the track iselevated above the point at which the chock plate 8 assumes its maximumelevated position under the force of the spring I6. This simple,positive locking means may include a rigid lock bar 25, pivotallymounted at 26-upon'a lug 21 ixed to the underside of the chock plate 8,which bar extends through the depending leg 28 of the angle II. Anenlarged head 29 formed on the rearward end of the bar 25 and engageablewith the leg 2B of the angle serves to limit the elevation of the chockplate 8.

A latchV plate 30 for engagement with the Vhead 29 of the lck bar 25,may be slideably mounted in a suitable slideway 3| fixed to the rearwardface of the angle leg 28 and is movable into a position overlying thehead 29 of the lock bar as indicated in Fig. 5. 'I'he latch 3i may becaused to assume this position by a weighted lever arm 32 pivotallymounted at 33 to the slideway assembly 3| and connected with the plate30 through the medium of an arm 34 pivotally connected, at its outer end35, to a link 36, the opposite end of the link being pivotally connectedat 21 to the latch plate 30. The length of the lever arm 32 may be suchas to cause the lower end J8 of the arm to engage with the ground orsupport 22 immediately prior to the engagement of vthe shoe I8 on thechock plate elevating lever I2, sothat the latch plate will be drawn tothe right (see Fig. 5) and clear of the head 29 when the shoe I8contacts with the surface 22 to permit the then elevated chock plate tofall to its inoperative position. Itis, therefore, apparent that thechock plate 8 may not become accidentally lowered to its inoperativeposition at any time when the track is in an elevated position and theWeighted lever arm 32 is free of contact with the supporting surface 22.

I have thus provided a simple yet highly eilicientv automatic chockingmeans wherein the chock plates 8 are caused .to assume their elevatedpositions through the relatively positive medium of the springs I6, whenthe track is elevated, without respect to the positions of the ramps 5and that, upon arrival at their maximum elevated positions, the chockplates are locked by positive means against accidental lowering untilthe lift is lowered to release the latch plates 30, as described. Ihave'furthermore precluded all possibility of injury to the ramp, thechock operating mechanism and' to the chock plates in the event that oneor both of the chock plates should be engaged, and thus held againstmovement, by the tires of the motor vehicle upon the track at a timewhen the track is lowered and the chock plate lowering levers I2 aremoved toward their dotted line positions as shown in Fig. 3. Inautomatic chocks of the type wherein the chock plate or member ispositively coupled with the ramp or other operating mechanism arrangedto move upon engagement with the supporting` surface 22, some damagemust occur either to the ramp, the chock member, or the inter-connectingoperating linkage, under the condition above suggested.

In Fig. 6 I have illustrated a more simplied form of the latch mechanismfor the lock bar 25. This form of the latching mechanism may comprise asimple weighted lever 40 pivotally mounted at- Il upon a plate 42secured as indicated at 43 to the steel angle I I. 'I'he upper end ofthe lever I0 may be formed with a portion 44 of enlarged area adapted tooverlie the head 29 of lock bar 25 when the parts are in the positionshown in Fig. 6, such position being the normal position of the leverwhen the track is elevated. When the track is lowered it would beapparent that the lever Ill would be moved in a clock-wisc direction,thus to cause the portion of enlarged area 4I to move out ofregistration with the head 29 of the lock bar and thereupon permit thechock plates to follow the descending movement of the lever I2.

While I have herein disclosed certain specific embodiments of myinvention, it is to be understood that such specific disclosure isillustrative amavo @tally molmted intermediate its length upon saidtrack having one end ele'with and movable relative to said chock memberand the other end provided with a shoe, and yielding means urging saidlever into a pomtion tocause the lever to engage with the chock memberto move the chock member about its pivot with its iree edge facing andin the path of a vehicle upon the track and to cause that end of saidlever having said shoe to move into a position whereby it may engagewith the Aground as the track is lowered.

2. In a motor vehicle lii't having a'horiaontal track arranged formovement along a vertical axis, automatic chock means comprising a chockmember pivoted adjacent one end' of the track and arranged normally tolie in inoperative position with respect to the track under the force ofgravity acting upon said member, a lever plvotally mounted intermediateits length upon said track having one end engageable with said chockmember and the other end provided with a shoe, yieldingfmeans urgingsaid lever into a position tocause the lever to engage with the chockmembertomovcthechbckmember aboutitspivot with its free-edge facing andin the path of a vehicle upon the track and to cause that end ofsaidlever having said shoe to move into a position whereby it may engage.with the ground, and means operable during the elevation oi the trackand ai'ter said chock member has been moved into the path of the vehiclefor locking the chock member'against movement, said last named meansbeing operable to release the chock member immediately prior to theengagement oisaidshoewiththegroimdasdurlngtbelowering of said track.

'3; In a motor vehicle lifthaving a track arranged to be raised andlowered, `a ramp pivoted adjacent one end Yof the track, a chock memberindependently pivoted coaxially with said ramp and an operating memberfor said chock member comprising a lever pivoted intermediate its endswith one end adapted to engage the chock and move it into operativeposition as the track is raised and the other end adapted to engage theground to move said ilrst end in a direction away from the chock as thetrack is lowered.

il.v In a motor vehicle lift having a track arranged to be raised andlowered, a ramp pivoted adjacent one end of the track, a chock member.

independently pivoted coaxially with said ramp, means Yseparate fromsaid ramp to engage the chock member and move it into its operativeposition as th track is raised, said means being moved in a directionaway from the chock by engagement with the ground as the track islowered, a latch to hold the chock member in operative position andvmeans engageable with the 1 mound to release sala man as the track isiowered.

5. In a motor vehicle lift having a horizontal ltrack arranged formovement along a vertical axis, a chock member'pivoted adjacent to oneend of said track and arranged normally to lle n inoperative positionwith respect lto said track when the .track is at its lowermostposition, a ramp member mounted at said end o! the track,

vand means including an operating member separate from said ramp memberand in unfastened the track is elevated, said operating member moving ina direction away from the chock member when the track is moved into itslowermost position whereby the chock member maydollow the operatingmember to assume its normal inoperative position. i Y

6. In ad motor vehicle lift having a horizontal track arranged formovement alongua vertical axis, a chock member pivoted at one endadjacent to one end of said track with its other end free and arrangednormally to lie in inoperative position with respect to said track whenthe track is at its lowermost position, means including an operatingmember engageable with and movable relatively to the chock member tourge the chock member about its pivot with its free end facing towardand in the path of a vehicle upon the track whenV the. track iselevated, said operating member moving in a direction away from thechock member when the track is moved into its lowermost position wherebythe chock member may follow the operating member to assume its normalinoperative position, and automatic means forlocking said chock memberin the path of said vehicle during the time that said track is elevatedaboveol predetermined level.

7. In a motor vehicle lift having a track arf ranged to beraised andloweredalong a vertical axis, a member pivoted at one end ladjacent toone end of said track with its other end free and arranged normally. tolie out of the path of a motor vehicle upony said track under the torceot gravity `acting upon said chock member. a ramp member at said 'end ofthe track, and means separate from said ramp member and engageable withand movable relatively to the vchock member to raise said chock memberabout its pivot from its normal pomtion toa position with its free atoneend of saidtrack with itsother edge free and arranged normally to'lieout of the path of a motor vehicle uponkaid track under the force ofgravity acting upon saidchock member, a 7

ramp member at said end ofg the trackL means separate from said rampmemberand engage- .ablewlth and movable relatively to the chock memberto raise said chock member' from its normal position to a position withits free edge facing and in lthe path of said motor vehicle when thetrack is raised from the ground against the 'torce of gravity actinguponthe chock memaway from the chock member when the track' is loweredto the ground whereby the chock member may fall to its normal positionunder the ber, said means being movable in a direction force of gravity,andpositive meansfconnected to f andy operable to limit the raising ofsaid chock member under the iniluence o! said ilrst-named means. f

'JAMES MLCUNNEEN.-

